Feature Request: Support for multiple Claude Code sessions with different accounts

Problem:
Currently, Claude Code doesn't appear to support running multiple instances with different Anthropic accounts simultaneously. When working across different projects or teams that may require different accounts (e.g., personal vs work accounts), users need to constantly log out and log back in.

Feature Request:
Add support for running multiple Claude Code sessions with different Anthropic accounts simultaneously, such as:

• Allow specifying an account profile when starting Claude Code (e.g., claude --profile work or claude --profile personal)
• Store credentials separately for each profile
• Provide visual indication in the terminal of which profile is currently active
• Allow switching between profiles without losing session context

Use Cases:

• Working on multiple projects that require different billing accounts
• Collaborating across personal projects and work projects simultaneously

Additional Context:
The current /login command allows switching accounts, but doesn't support maintaining multiple active sessions simultaneously in different terminals.